An informal online search on ‘weight loss’ through a popular search engine for the purposes of this article yielded over a billion (a thousand million) hits. This is not surprising, since market research has found that almost two-thirds of British adults are on a weight-loss diet ‘most of the time’ and almost half had tried to lose weight in the previous year (Mintel, 2016). It is also big business; the first page of the online search had 15 sites and nearly half were adverts for commercial organisations making claims for their weight-loss programmes. Despite this, in the UK, obesity rates nearly doubled between 1993 and 2011, from 13% to 24% in men and from 16% to 26% in women (National Institute for Health and Care Excellence (NICE), 2014).
This is important to nurses, because being too heavy impacts upon other aspects of people's health (Milder et al, 2014). Further, if people are too heavy and achieve weight loss, this benefits their physical (Ades and Savage, 2014) and mental (Livantsova et al, 2018) health. The health professional press recognises that, despite decades of research, strategies to tackle obesity are often unsuccessful (Eichorn and Jevert-Eichorn, 2021). Advising clients/patients is complex and many nurses feel under-prepared for this (Keyworth et al, 2013). Added to this, nurses themselves are not exempt from being too heavy themselves and, at least for some, this can add to their discomfort in advising clients on lifestyle modifications (Pearce, 2020).
This article discusses some recent evidence about the most popular interventions. The aim is to provide nurses with an overview of potential strategies for advising and helping clients who wish to lose weight, along with some pointers to interventions that are beyond the scope of most nurses. The article begins with a review of the need for weight management and discusses the possible targets for those who need to lose weight. It will review a range of different diet regimens that clients may adopt and some of the advice a nurse may offer. It then goes on to outline approaches that may be beyond the nursing remit, which is physical activity, drug interventions and, finally, surgical approaches. Although these may be beyond the role of most nurses, clients may ask nurses about them and this article helps nurses consider possible responses. The emphasis is on the UK context, and the research articles included are from the UK where possible.
The need for weight loss
First, nurses must identify whether the client seeking help does indeed need to lose weight. The requirements of fashion are more rigorous than those for health, and many people wish to lose weight for aesthetic rather than health reasons. Advising such people is outside the scope of this article, along with caring for those who are underweight.
One of the best-known measures for weight is the ratio of weight and height. This is often expressed as the body mass index (BMI) and is calculated from an individual's measurements of height and weight.
BMI = weight ( kg ) hight ( m ) 2
This is a useful ready reckoner, but it is not unfailingly accurate. People who have an unusual physique require different assessments. Famously, people with very high muscle mass have a high BMI due to muscle being heavier than adipose tissue, yet such people are not truly overweight or obese because they do not carry too much adipose tissue. An article by Hosie (2017) in The Independent featured a personal trainer who claimed to have been informed he was obese. BMI should therefore be interpreted with caution.
To be very large is bad for health. For some years there has been controversy regarding people with a BMI of 25-29 because these people seemed quite healthy. However, Klatsky et al (2017) followed up a heterogenous sample of more than one quarter of a million people for 30 years. They found the relative risk of dying (from all causes) was 1.1 for people with a BMI lower than 18.5. Which means that if 100 people of normal weight died, then 110 people who were underweight would die. This was the same risk as those with a BMI of 25-29. The relative risk of dying for people of varying BMIs is presented in Table 1.
Table 1. Definitions of obesity with relative risk of dying over 30 years
|Body mass index||Category||Relative risk of dying|
|18.6-24.9||Ideal or normal weight||1 (the reference)|
|25-29.9||Pre-obese or overweight||1.1|
|>40||Obesity 111 or morbid obesity||2.7|
A recent meta-analysis of 23 studies (Opio et al, 2020) provided further convincing evidence that being overweight or obese is a risk factor for illness. Opio et al (2020) showed that being overweight incurs a risk of developing cardiovascular disease and this risk is present even in the absence of other risk factors such as hypertension or diabetes. They calculated the relative risk of a cardiovascular event as 1.58 for obese people, compared to those of normal weight. The relative risk for overweight adults was 1.34. Opio et al (2020) argued that the term ‘healthy and overweight or obese should not exist’.
As identified above, BMI can be misleading, and it is possible that waist measurements can be more accurate. This is because excess body fat around the middle—the site of important organs—is particularly damaging to health. The NHS website (2018) recommends that, regardless of height or BMI, an individual should seek to lose weight if they have a waist measurement of more than 94 cm (37 in) for men and 80 cm (31½ in) for women. Individuals are at very high risk if their waist measures 102 cm (40 in) or more for men and 88 cm (34 in) or more for women. A more complex calculation is to assess waist circumference to height ratio (Smolinski et al, 2018).
Targets for weight loss
For people who need to lose weight, the NHS website (2019) recommends losing 0.5-1 kg (1-2 lb) a week. Many people would like to lose weight more quickly than this; it is interesting to note that the online search described above suggested the default search of ‘lose weight fast’. Coutinho et al (2018) discussed the fact that rapid weight loss could be associated with a greater loss of fat free mass (most individuals should aim to lose weight from fat stores) and a reduction in basal metabolic rate (BMR), which would mean the individual uses less energy most of the time (which would make weight loss more difficult). Box 1 provides an explanation of BMR and energy.
Box 1.Expressing energy in the dietHealthcare has now mostly adopted the SI system of units, and energy is measured in Joules. However, many people prefer the traditional calories and nurses may need to be familiar with both.1 kilojoule (kJ) = 1000 joules1 megajoule (MJ) = 1 000 000 joules1 kilocalorie (kcal) = 1000 calories, or 1 ‘dietary calorie’To convert from one unit to another:1 kcal = 4.184 kJ, so a 1000 kcal diet provides 4.184 MJ or 4184 kJ1 MJ = 239 kcalThe basal metabolic rate (BMR) is the rate at which a person uses energy to maintain the basic functions of the body—breathing, keeping warm, keeping the heart beating—when at complete rest. An average adult will use 4.6 kJ (1.1 kcal) each minute to fulfil BMR. To estimate energy requirements, BMR is multiplied by the physical activity level, which is usually between 1.4 to 1.9, depending upon how active the individual is.So, energy expenditure = BMR x physical activity level.Using this, most men require 8.77-10.6 MJ/day (2100-2550 kcal/day) and most women require 7.61-8.1 MJ/day (1810-1940 kcal/day)Source: adapted from the British Nutrition Foundation (2009)
To investigate, Coutinho et al (2018) compared two groups of obese clients: one lost weight rapidly while the other lost weight steadily. Once a stable weight was achieved, no difference in body composition was found, which the researchers acknowledge was unexpected. On the other hand, those who had lost weight slowly retained a higher BMR and used more energy while exercising. This suggests that those who had lost weight slowly may be able to maintain their new weight more easily but, unfortunately, Coutinho et al (2018) did not continue the observations long enough to confirm this. They do note, however, that those in the rapid weight loss group experienced less severe hunger, possibly due to the appetite-suppressant effect of ketosis. However, these findings are contradicted by Hintze et al (2019), who used a similar approach to compare obese women dieters and found no evidence of a decrease in BMR or appetite in either the rapid or steady weight loss groups. Both groups were equally successful but, again like Coutinho et al (2018), there was no long-term follow-up. This is important if those who lose weight rapidly are likely to be more prone to regaining it. Yet Vink et al (2016) found no difference between dieters who lost weight quickly and those who did so slowly. Since many clients seek rapid weight loss and this is often encouraging and motivating for them, nurses may need to reconsider some traditional advice.
Strategies to achieve weight loss
Nurses may first need to review their own belief system and behaviours. It appears that negative stereotypes and stigmatising of obese clients by health professionals continues and, in contrast to other negative stereotypes, can even be perceived as socially acceptable (Phelan et al, 2015; Pervez and Ramonaledi, 2017). This can express itself with the professional less likely to engage in client-centred communication with the obese client, to be less respectful, and to hold lower expectations of concordance or of a successful outcome (Phelan et al, 2015). This adds to the client's anxiety and tendency to avoid health care.
There is only one way to lose weight, and that is to take in less energy than is used (Thomas et al, 2012).
Weight change equals energy input less energy output. In mammals, energy input is only in the form of diet. Energy output is all the energy used to sustain life (see Box 1 for some details of this). Therefore, to lose weight, clients must take less energy in the diet compared with the amount they use. The simplest, and least controversial, way to lose weight is through restricting energy intake in the diet—calorie counting.
Calorie counting: the NHS approach
The NHS recommends people who wish to lose weight should restrict their calorie intake over a period of 12 weeks (NHS website, 2019). It is based on women taking no more than 5.8 MJ (1400 kcal) a day and men taking no more than 7.9 MJ (1900 kcal) a day. This should lead to a weight loss of 0.5–1 kg (1–2 lb) a week. The NHS website (and there is a free app for smartphone users) provides a wealth of recipe suggestions, activities and motivating reading to help with this, for the reality is this is hard work and can be discouraging. One issue that is almost certain to arise is the occasional eating of more than the scheme allows. There is a danger that, having made one mistake, the dieter abandons the diet for the remainder of the day or longer. The NHS counters this by recommending reducing the energy intake the following day. However, this may be unduly harsh, and the nurse may prefer to encourage the dieter to resume the usual diet as soon as possible, rather than appearing to punish the mistake.
There is a wide variety of food products marketed to people who wish to lose weight. Most are labelled ‘low fat’, ‘low calorie’ or ‘no added sugar’. Although occasionally useful, these may not be suitable for long-term use. There is some evidence that foods adapted to be ‘healthy’ in one respect are less helpful in others, to make the food more palatable. Thus Nguyen et al (2016) found foods marketed as low fat had more sugar in them, although the overall energy content was lower. Further, there is a risk that foods marketed as low fat will lead to people believing them to be healthy and eating more (Geyskens et al, 2007). People can also get bored. Turnwald and Crum (2019) investigated the effects of labelling foods and found that those marketed as ‘tasty’ were chosen more often in the long term compared to the same food marketed as ‘healthy’.
It is simpler, and possibly more successful in the long term, for people to simply eat less. Portion sizes have increased over the past few decades (Zheng et al, 2017), and this has led to people expecting to eat more. In a series of experiments, researchers in Liverpool (Robinson and Kersbergen, 2018) showed that the perception of what is normal can be recalibrated, so people choose to eat less. This is a gradual process and could be encouraged by simple strategies such as using smaller plates (Pratt et al, 2012).
Taking a low energy diet for 12 weeks to achieve modest weight loss is difficult for many, and there are schemes that nurses could consider recommending.
One possible approach is to use fitness trackers, of which there are several on the market. They claim to provide the wearer with information about energy usage. The wearer can then use that information to plan their diet. One potential and serious problem is that they may overestimate the energy used. An investigation for BBC News (2019) found that most fitness trackers overestimated energy use, some by as much as 50%. Brooke et al (2017) also found that trackers were inaccurate, especially when used by adults who were ‘free living’, in other words, those who were not engaged in supervised activities and exercise. The makers of the fitness trackers told the BBC that their devices were based on ‘extensive research’ (BBC News, 2019), but acknowledged that they are not medical devices.
Clubs and support groups
If the client is seeking more support and encouragement than their health professional can provide, they could consider joining a commercial organisation, such as Weight Watchers or Slimming World. These organisations provide upbeat, motivational materials and contact with others, which can provide the all-important encouragement. They often use simple diet schemes using points, which some may find simpler than calorie counting, although that is what they are based on. These are commercial organisations that charge a regular fee, typically over £5.00 a week. This may be a problem for some people, but others find this a helpful motivation to keep going with the scheme.
Intermittent fasting (‘the 2:5 diet’)
A potential approach to energy restriction is intermittent fasting. This has been practised by religious communities for generations (Hoddy et al, 2020). Intermittent fasting can involve different patterns, but for weight loss typically involves eating normally (ie, to meet energy expenditure) most days but severely restricting energy intake on just a few days. One pattern is to eat to requirements 5 days a week and to eat between one-quarter and one-third of energy requirements on 2 days a week (the 2:5 diet). A recent review (Welton et al, 2020) found several trials demonstrating that this approach is promising for weight loss, although the review authors comment that the trials varied in their approach and were all of short duration, the longest-lasting trials were 12 months.
- Good glycaemic control
- An alteration in gut flora to encourage energy usage in the person; increased levels of adiponectin and decreased levels of leptin in the blood, which could improve energy usage and decrease appetite
- Changes to circadian rhythms that may promote cardiac health.
Further, intermittent fasting may lower inflammatory markers, which are often increased in obesity and may cause some of its associated complications. At least some of these changes appear independent of weight loss (Hoddy et al, 2020). Finally, and perhaps most importantly, dieters may find they can sustain intermittent fasting indefinitely, because it is flexible, does not require severe, sustained monitoring of their diet, and is often not characterised by unpleasant hunger (Hoddy et al, 2020).
All the methods discussed so far involve making daily choices in food, which some people find confusing, difficult and depressing. One possible approach is meal-replacement schemes. This is where two or three meals a day are replaced by a specialised, purchased drink. These are very low energy yet must, by UK law, provide certain nutrients and so the dieter can be assured they are likely to be taking in the essential nutrients without having to calculate this. These can be successful in lowering blood sugar (König et al, 2014) or reducing body fat (Shih et al, 2019). However, these trials typically last for only a few months (just 8 weeks in the case of Shih et al (2019)) and it is possible that, on their own, they do not help the dieter learn to choose and sustain a healthy diet. Further, the foods may include unacceptable amounts of salt and low amounts of fibre (Shih et al, 2019) are expensive and can cause the dieter to miss the pleasure of eating meals with friends.
Alternatives and supplements to energy restricted diets
The World Health Organization (WHO) describes physical activity as any bodily movement produced by skeletal muscles that requires energy expenditure (WHO, 2020). This can comprise any routine activity, such as housework, gardening or walking the dog. Exercise is a subgroup of physical activity where activity is planned, structured, repetitive, and aims to improve or maintain one or more components of physical fitness. Examples of exercise include any sport, swimming, dancing, or simply walking.
The health benefits of regular physical activity are irrefutable and the WHO recommends that all adults should undertake at least 150 minutes of moderate aerobic activity a week alongside some vigorous and muscle-building activity (WHO, 2020). Thus, most obese adults should increase their physical activity. This may need to increase gradually if the client is very unused to strenuous activity. The target, however, is to include 45-60 minutes' activity of moderate intensity each day. The activity is more likely to be sustained if it is enjoyed and can be incorporated into everyday life. In the UK, exercise is available on prescription, and this can vary between supervised activities or simply free membership of a club. In any event, it is unlikely to extend beyond 3 months.
It is misleading to imply that the energy required for most activities will, in the first instance, lead to weight loss. A meta-analysis conducted by Thomas et al (2012) concluded that some people may decrease their resting metabolic rate when they exercise. This unhelpful effect was most pronounced in those who were not obese, and obese subjects used more energy during and after exercise. Further, exercise is an appetite stimulant and Thomas et al (2012) suggested there was a risk that people may increase their energy intake following exercise.
Gobbo et al (2019) reviewed prescriptions for Nordic walking for obese patients. This involves walking using a long walking stick in each hand. This was chosen as a realistic form of exercise that would not be too arduous and could be fun. They found that most of the review papers reported positive improvements to body fat and blood sugar control. This was most prominent when the exercise was supervised and occurred about 4-5 times a week. Sanchez-Lastra et al (2020) also found some benefits in prescriptions for Nordic walking among obese clients, but these were no greater than in the control group.
However, an increase in physical activity is part of almost all weight-loss programmes and there are several reasons for this. Energy restriction on its own leads to generalised loss of weight but accompanying the diet with exercise can lead to a loss of adipose tissue and preservation of lean body mass, or muscle tissue. This could increase resting energy rate and thus BMR. Adding exercise to diet programmes increases cardiovascular health (Blumenthal et al, 2010), and improves sleep and emotional wellbeing.
Sometimes, however, dietary restrictions and exercise are insufficient and the nurse may need to consider further interventions.
People on weight-loss diets must reduce their energy intake but their need for other nutrients usually remains the same. Nurses should consider whether the dieter needs nutritional supplements, especially of lipid-soluble vitamins and essential fatty acids (Iglesia et al, 2019). This is because, for reasons not fully understood, obese people are often undernourished in some of the micronutrients (Ruxton, 2011) and a weight loss diet could compound this.
There are drugs available that may assist with weight loss, although some are not approved in the UK or Europe because of safety concerns (Woloshin and Schwartz, 2014). Patients learn about these online and may be keen to take them, encouraged by tales of success included in online forums (Fox et al, 2005).
They work through a variety of mechanisms, which are outlined below:
- Orlistat (Orlos) is the only drug that has been approved specifically for the control of obesity in the UK. It inhibits lipase and thus reduces the absorption of dietary lipid. The lipid therefore remains in the bowel, which can cause discomfort
- Naltrexone with bupropion (Mysimba) is a serotonin and nor-adrenalin reuptake inhibitor. It has been used within the NHS to help with weight loss but is no longer recommended (NICE, 2020) due to its unacceptable neurological effects
- Liraglutide (Saxenda) is administered subcutaneously and activates the glucagon-like peptide receptors. This increases insulin, decreases glucagon and delays gastric emptying, leading to appetite suppression and feelings of fullness. Its use is approved in the UK, and it can be obtained through the NHS. As part of a well-managed weight-loss regimen, it leads to a loss of about 6 kg in the first year, but the effect may reduce after that, and it is accompanied by some gastrointestinal discomfort (Margulies et al, 2016)
- Lorcaserin (Belvic) is an agonist of the 5-HT2C receptors in the hypothalamus, which suppresses appetite. It was never approved in the UK and was withdrawn from the US market in January 2020, following concerns that a higher-than-expected number of patients taking it were subsequently diagnosed with colorectal, pancreatic and lung cancers (Woloshin and Schwartz, 2014)
- Phentermine and Topiramate are often taken together (Qsymia). Phentermine is a sympathomimetic drug and increases metabolic rate. Topiramate is an anticonvulsant drug that stabilises the membranes of neurones and reduces appetite. However, Qsymia is not currently available in the UK, due to concerns about possible addiction and other mental health problems.
People who are obese 111 or obese 11 with comorbidities (Table 1) and have not responded to other interventions may require bariatric surgery. Arterburn et al (2020) reviewed these procedures and found that they lead to good weight loss. There were other benefits, for example, patients with type 2 diabetes showed improved glycaemic control (Kashyap et al, 2013) and patients with hypertension or sleep apnoea showed improvements to their conditions. Arterburn et al (2020) acknowledged these are major procedures on unwell patients but showed the mortality has much improved to 0.03-0.2%.
Recently updated guidelines from NICE (2021) stated that surgical interventions are only appropriate when lifestyle interventions have failed. Even then, surgery is only suitable for those who have a BMI of more than 40, or more than 35 with comorbidities, who are generally well, and where specialist facilities for full assessment and follow-up are available. There may also be some long-term disadvantages of these procedures. For example, Yu et al (2019) found a slight increase in non-vertebral fractures following gastric bypass, which could be explained by a deficiency in some micronutrients, and patients are advised to take nutritional supplements postoperatively and for a significant period of time.
This article has shown that many adults need to lose weight and wish to do so, but it is a complex and long-term undertaking. The nurse is well placed to offer dietary advice. This must involve the client taking in less energy than they use. Several strategies can assist with this and the nurse and client can select that which the client feels is most sustainable. This may involve a certain amount of trial and error as the client strives to adjust the habits of a lifetime to find a lifestyle that they can maintain in the long term. The client is also likely to require an increase in physical activity. Although this need not be a formal exercise programme, it should include up to an hour of moderate intensity most days. For some clients, however, this is insufficient, or they are unable to comply, and the nurse may need to refer them for further interventions, which are likely to be medication or surgery.
The nurses' guidance, based upon a sound scientific rationale, should be accompanied by sympathetic encouragement to help the client continue despite disappointments and setbacks as the client seeks to build their future based on a prospect of good mental and physical health.
- Being overweight is bad for a person's long-term physical and mental health. The only way to lose weight is to use more energy than is taken in
- Many people adopt weight-loss diets, which are big business. Nurses may need to conduct a careful assessment of whether clients really do need to lose weight and, if they do, encourage them to adopt an evidence-based approach to setting their weight targets and managing their weight
- Rapid weight loss is encouraging for clients and there is limited evidence of it being less helpful than steady weight loss
- The NHS encourages the use of ‘calorie counting’, but not all foods marketed as ‘low fat’, ‘no added sugar’ or ‘low calorie’ are useful in the long term. Some clients may be suitable for other approaches such as intermittent fasting
- If these approaches are not successful, surgery or pharmacological interventions are sometimes appropriate
CPD reflective questions
- Review the packaging of foods marketed at dieters. Is the product information useful and accurate?
- What is your attitude to your own body weight? Does this impact on your therapeutic relationships and how helpful is that?
- Sometimes, people who are heavy avoid attending for health care, perhaps because they fear their weight will be discussed. What can you do to overcome this?